To speed up the printing speed of an inkjet printer, the manufacturers normally focus on increasing the droplet frequency response. Hence, it has become a very important technique to measure the droplet frequency response of an inkjet printhead. A magneto-electric method is proposed to measure the droplet frequency response. The magneto-electric apparatus contains a metallic detecting plate and a magnetic ring with a gap of about 100 microns filled with a nonmagnetic insulating material. The magnetic ring itself is made of a high-permeability alloy consisting of about 78% nickel and 22% iron. When an ink drop jetted from a nozzle makes a contact with the metallic detecting plate, which is perpendicular to the nozzle plate of a printhead. a current is conducted through the detecting plate immediately, and detected as a portion of expected signal. The expected signal is then processed by a signal processing circuit for counting the number of jetted drops, and determining the maximum droplet frequency response of the inkjet printhead as a function of the driving frequency of an applied voltage across the printhead.